In-situ synchrotron computed tomography images of a tensile test on a carbon fiber-epoxy composite for mechanical damage analysis

Using synchrotron computed tomography, we have obtained 3D images of a carbon fiber-epoxy composite laminate loaded under tension. A double-edge notched specimen with a notch section area of ~ 1 mm × 1 mm is cut using waterjet machining from the [904/05]s laminate with 7-µm nominal fiber diameter. It was loaded under continuous tension, with a deformation rate of ~ 1.4 μm/s, and in-situ scanned with a propagation distance of 60 mm, a beam energy of 20 kV, and 1000 projections per scan, each with an exposure time of 9 ms. The magnification was 10×, and the voxel size was 1.1 μm. The test was conducted at the TOMCAT beamline of the Swiss Light Source (SLS) in Villigen, Switzerland. The reconstruction was performed using an absorption-based algorithm provided by SLS.

Eight 3D image (out of ~60 images) corresponding to eight loading steps with nearly the same force intervals are selected. These eight steps (Step 0 - 7) are identified on the force-displacement curve that is included in the dataset. The 3D images are overlaid on top of each other (registered), using 3D rigid transform by “Normalized Mutual Information”, and resampled with “Standard” (linear) interpolation, in the commercial software Avizo 2019.1. The empty space around the specimen is cropped out in each image. The eight 3D images are uploaded to this dataset in the folder "Full volumes (no filter)". Moreover, a smaller volume of interest (VOI), with a size of 330 × 580 × 630 μm3, is selected, which is shown with a blue box in the schematics available in the dataset. This volume is copped from the full volume. The eight small VOIs are also uploaded to this dataset in the folder "Cropped VOIs for analysis of damage interaction (non-local means filter)". The image noise in the small VOIs is reduced using a 3D “non-local means” filter with a search window of 10 px and local neighborhood of 3 px, using Avizo 2019.1. These 3D images are used for real-time analysis of mechanical damage in carbon fiber composites. We have performed this using digital image correlation in the reference article "Mehdikhani et al., Digital volume correlation for meso/micro in-situ damage analysis in carbon fiber reinforced composites". Other techniques can be employed to characterize the damage and the evolution of the microstructure in these images.

采用同步辐射计算机断层扫描技术，本研究获取了碳纤维环氧复合材料层压板在拉伸载荷作用下的三维图像。通过水射流加工，从[904/05]s层压板中切取了一个具有约1 mm × 1 mm缺口截面积的样品，该样品的纤维直径为7微米。样品在持续拉伸载荷下进行加载，变形速率为约1.4 μm/s，并在现场扫描，扫描距离为60毫米，束能为20 kV，每扫描1000个投影，每个投影的曝光时间为9毫秒。放大倍数为10倍，体素大小为1.1微米。实验在瑞士光子源（SLS）位于瑞士维利根的TOMCAT光束线进行。重建工作采用SLS提供的基于吸收的算法完成。

从约60张图像中选取了八个与加载步骤相对应的三维图像，这些步骤的载荷间隔几乎相同。这八个步骤（步骤0 - 7）在数据集中的力-位移曲线上进行了标识。三维图像通过“归一化互信息”的三维刚性变换进行叠加（配准），并使用“标准”（线性）插值重新采样，操作在商业软件Avizo 2019.1中进行。在每个图像中裁剪掉样品周围的空白区域。这八个三维图像上传至数据集的“完整体积（无滤波）”文件夹中。此外，还选取了一个较小的感兴趣体积（VOI），其大小为330 × 580 × 630 μm³，在数据集中的示意图中以蓝色框标出。该体积从完整体积中裁剪而来。这八个小的VOI也上传至数据集的“裁剪VOI以分析损伤相互作用（非局部均值滤波）”文件夹中。使用Avizo 2019.1中的3D“非局部均值”滤波器，搜索窗口为10 px，局部邻域为3 px，对小型VOI中的图像噪声进行降低。这些三维图像用于碳纤维复合材料机械损伤的实时分析。我们已在参考文献“Mehdikhani等人，数字体积相关技术在碳纤维增强复合材料中微/中尺度原位损伤分析中的应用”中进行了这一分析。其他技术也可用于表征这些图像中的损伤及其微观结构的演变。